Diversity on LTE modems - Do I need it - some clarification please?

IoT Modules General wireless topics
1

I’m looking for some clarification about the operation of the DIV antenna port on the WP7607 LTE module, as there seems to be conflicting information or viewpoints out there.

My application doesn’t require high data rates, but operation in marginal signal is important Why am I opting for LTE if I don’t need the bandwidth? Simply because 3G is in its twilight days and LTE will ultimately give me better coverage.

Traditionally Diversity means “Select whichever antenna has the strongest signal”, but in LTE it seems to be used for MIMO in order to give a higher bandwidth. I found this during Googling:

When signal strength or quality is low, it’s difficult for the modem to distinguish between the two data streams, so when signal levels drop below a certain threshold level, MIMO is switched off and the modem operates with only one antenna (Port 1 on Sierra Wireless modems).

I can see that DIV is receive only, yet the Tech Reference doesn’t say much about it but lists it as a mandatory connection. so

  1. Do I need it?
  2. If not, should I terminate the pin?

I’d like to not fit it if possible as I’m a bit short on space, plus it’ll be one less connector and antenna off my BOM.

2

@sciscitatio,

Short answer is that the units will work without the second antenna, on LTE you limit your performance but it will operate fine. If you don’t use it just leave it floating.

Regards

Matt

3

Hi Matt sorry for a late reply. Thanks for the info, so I take it the text I quoted in my message is accurate then - i.e. the Aux/Diversity antenna is for throughput?

Makes my life a bit easier :slightly_smiling_face:

4

Diversity enhances signal quality. It will impact throughput, range and power consumption. You might experiment by taking note of the average CQI that is achieved with one vs two antennae.

5

Hello,
I’m jumping in to ask a related question. We often install remote sites in poor cell coverage areas, so we try cell boosters with mixed results. Should I use a booster for both Main and Diversity? We have experimented with a booser on main only and main and div, with no noticeable difference - still poor operation. BTW what make and model booster does SW recommend?
Thanks George